1. Field
Aspects of the present invention relate to a secondary battery.
2. Description of the Related Art
In general, secondary batteries are rechargeable, in contrast to primary batteries, which are not rechargeable once discharged. Secondary batteries are widely used in various applications including advanced electronic devices such as cellular phones, notebook computers, camcorders, etc.
Lithium secondary batteries operating at 3.6 V are rapidly replacing nickel-cadmium (Ni—Cd) batteries or nickel-hydride (Ni-MH) batteries, which have widely been used as power sources for electronic devices, because the operating voltage of these lithium secondary batteries is approximately three-times higher than that of nickel-cadmium (Ni—Cd) batteries or nickel-hydride (Ni-MH) batteries. Lithium secondary batteries also have excellent energy density per unit weight.
Lithium secondary batteries generally employ a lithium oxide positive active material, and a carbon negative active material. Such lithium secondary batteries may be classified as liquid electrolyte cells or polymer electrolyte cells based on the kind of electrolyte used. Lithium batteries using a liquid electrolyte are generally referred to as lithium-ion batteries, and lithium batteries using a polymer electrolyte are generally referred to as lithium-polymer batteries. Typically, lithium secondary batteries are manufactured in cylindrical, rectangular, or pouch-type shapes.
In typical lithium secondary batteries, an electrode assembly is inserted into a case together with the electrolyte or electrolytic solution. However, the electrode assembly within the case is often susceptible to being damaged due to external impacts on the secondary battery or case. Accordingly, secondary batteries are often subject to short circuits or other safety concerns resulting from these external impacts.